Die press



3 Sheets-Sheet l Inventor l llllll @Il H. M. WILSON May 5,v 1959 DIEPRESS Filed Feb. ll, 1955 May 5, 1959 Filed Feb. l1, 1955 H. M. WILSONDIE PRESS 5 Sheets-Sheet 2' ,lo i

May 5, 1959 l H. M. wlLsoN 2,884,822

DIE PRESS Filed Feb. l1, 1955 5 Sheets-Sheet 3 ttorney United StareParent DIE` PRESS Hugh Morton Wilson, Newton Mearns, Scotland, assignerto The International Nickel Company, Inc., New York, N.Y.

Application February 11, 1953, Serial No. 336,387

Claims priority, application Great Britain February 13, 1952 1 claim.(ci. 78.-'18) This invention relates to deep die presses; that is to`say to presses in which one of two press surfaces is formed on the endof a punch and the other is formed at the bottom of a recess in a die,and in which when the press is closed the punch makes a sliding t in therecess and the press surface on the punch together with the surfacesofthe die-recess, including the press surface at the bottom of thedie-recess, define a totally enclosed cavity. Such presses maybe usedfor producing metal articles of precise shape, from hot blanks ofapproximately correct shape. To ensure precision in the shape of thefinal article, the blank is usually subjected to very high pressure by"which themetal is forced into contact with the entire area of the presssurfaces. As a result, it may prove ditlicult toI remove the articlefrom the recess after the plunger has been withdrawn.

' When tough metals for high temperature use, such as nickel/'chromiumbased alloys are being handled, the pressures are so high, for example100 tons per square inch, that it is not feasible to provide ejectorpins such as are frequently used in die-casting dies and the like inwhich pressures are comparatively low.

Itis anA object of the present invention to provide. fa deep die pressin which an article can be subjected to high pressure and thereafterremoved.

It is a further object to provide a method of deep die pressing articlesof tough metal for high temperature use.

It is a more specific object to provide a deep die press for forming theblades of gas-turbines.

In carrying out the present invention the die is made in more than onepiece, each piece carrying part of the press surface in the recess, andat least one piece is mounted to rock from a position it occupies duringpressing to a position in which it or some other piece of the die breakscontact with an article in the recess, so facilitating removal of thearticle from the recess.

Preferably the rocking of two or more pieces serves both to break fullcontact of these pieces with the article and also to shift the articleentirely out of contact with a stationary piece or pieces of the die. Itmay be sufficient to lift the article clear of the stationary piece orpieces.

Preferably the axis about which each piece can rock is such that theforce to which the part of the die surface on the piece is subjectedduring pressing has a moment tending to hold the piece in position.

Preferably the rocking of each piece is effected automatically on thereturn stroke of the punch. This may conveniently be done by providing alost-motion connection between a holder for the piece of the die and thepart which carries the punch.

For many articles the die may be made in three pieces, namely astationary central piece and two end pieces which rock to eject thearticle.

The invention has been particularly developed for use in the manufactureof double-rooted gas-turbine blades. The main steps n such manufactureare the hot rolling ICC of a billet to a dumbell-shaped' blank, hotpressing of the blank into a rough blade, and machining to final shape.Hitherto the pressing has not been carried out in deep dies because ofabsence of means for removing the rough blade from the recess of a deepdie. Instead a series of pressing operations have been necessary inshallow dies with intermediate shearing operations to remove flashes Noflashes occur in deep die pressing.

The preferred press for deep die pressing of a rough double-rootedgas-turbine blade from a dumbell-shaped blank will now be described indetail with reference to the accompanying drawings, in which: K l

Figure 1 is a half elevation and half section on the line l-I in Figure2; Y

Figure 2 is a horizontal section on the line IIL-II in Figure l;

Figure 3 is a vertical section on a larger scale on the line III-III inFigure 2; and

Figures 4 and 5 are vertical sections showing some of the parts ofFigure l in different operating positions. l

The press consists of a die mounted with its recess open upwards on abase plate 4, and a punch 6 mounted on a reciprocating stem 8.

The die 2 consists of a central piece 10 with a trough 11 in which theblade proper is pressed, and two end pieces `12 and 14 with cavities 13and 15 in which the roots of the blade are pressed. The punch 6 iscomplernentaryl to the whole composite die. The central piece 10 of thedie is mountedin a holder 16 keyed at 18 to the base plate 4. One sideofthe trough is supported by a fixed abutment 20 on the holder while theother side is supported" by screws 22 passing through the holder. Inaddition the underside of the central piece has a shallow central recessl24 so that downward pressure on the bottom of the trough 11counter-acts to some extent the tendency of the sides of the trough tospread under lateral pressure. .The -central piece is held down byclamps 26 screwed to the holder 16.

Each end piece 12 and 14 of the die is mounted in an end face of aseparate block-like holder 28 mounted to rock about a fixed horizontalshaft 30 which is transverse to the axis of the trough 11 in the centralpiece and is carried in two blocks 32 bolted to the baseplate 4. Thisshaft passes through the end of the holder remote from the die piece 12or 14, which has a bevelled face 34 to lit against a similarly bevelledend face 36 on the central die piece. Thus the end die piece in itsholder can rock upwards about the shaft without jamming against thecentral die piece. The holder of each end die piece has a step 3S on itsunderside facing away from the centre of the die, and a strip 40 letinto the baseplate serves as an abutment for this step. The force on thepress face of the end die piece during pressing tends to rock the enddie piece downwards, and this tendency to rocking is resisted partly bythe abutment and partly by the engagement of the two bevelled faces 34and 36. In addition the abutment resists the axial component of theforce.

The punch 6 is mounted in a further holder 42 screwed to the lower endof the main reciprocating vertical press stem 8. On this holder ismounted a crosshead 44 which can slide over two tie-rods 46, eachpivotally connected at its lower end 48 to the top of one of the holders28 for the end die pieces. Above the crosshead each tierod carries twolock nuts 50, and a washer 52 with a part-spherical under surfaceinserted between the lock nuts and the upper surface of the crosshead. Asliding guard 54 (shown in Figure l) is fitted to the holder 42.

In operation, a dumbbell-shaped blank of nickel/chromium based alloy isprepared by rolling preferably by means of an apparatus as described andclaimed in my U.S. application Serial No. 180,750, filed August 22,1950, now U.S. Patent No. 2,686,442. Before each blank is pressed, thepunch 6 is moved to the position shown in Figure 1 and the heated blankis then placed in the recess in the die 2. The punch 6 is then forceddownwards into the position'shown in Figure 4 and continues to move downuntil the blank has become so pressed that it entirely lills theremaining space between thepunch and the die.

j The punch is then withdrawn and on its return stroke is carried abovethe position shown in Figure 1 into the position shown in Figure 5. Inthis movement the crosshead 44 raises the tie-rods 46, thus rocking thetwo holders 28 for the end die pieces and lifting the rough blade 56right out of the central piece so that it can be grasped lin tongs.- Thepunch is then moved downwards again far enough t o allow the holders 28to rock back to theirV initial position, and is stopped to let the nextblank be inserted. jxTo, elirninate anyrisk.of the roots of the roughblade jamming in the end die pieces, the side pressfaces of these piecesare flared in a horizontal direction at a small angle, say 2.

-..Since in deep die pressing there is no ash, the volume of the `blankdetermines the thickness of the rough blade. Accordingly, betweenrolling and pressing, each blank may need to be roughly machined tobring it to a definite volume. Moreover the blank is shaped, within thelimits of .simple rolling and turning, so that the ow of metalinpr'essing is a minimum.

,"The blank is also shaped so that initially no metal touches the jointsbetween the die pieces. This is to ensure that no metal escapes as ashesat the joints before the abutting faces are fully forced together by thepressure'in the die to resist penetration.

. After pressing, the blade will usually require nal light machining,but with skill in the pressing this stage may be omitted.

The procedure described in detail may be applied to the manufacture ofsingle-rooted blade. The punch and die are modified in shape, one of themovable pieces of thedie forming the root while the other forms the tipof the blade. The press is supplied with mushroom-shaped blanks.

I claim:

A die press for forming an article by deep die pressing in a deep dierecess comprising a reciprocal punch, a die capable of cooperating withysaid punch to form a pressed article from a blank, and a mounting tosupport said die, said punch and die together forming an enclosed cavitywhen the punch is in the closedposition in the die, said die comprisinga plurality of die pieces forming a die recess to receive a blank to bepressed by said punch, said plurality of die pieces comprising a diepiece fixed to said mounting and two end die pieces pivotally supported-by said mounting to rock relatively to the ixedly-mounted die piecefrom a position permitting pressing of a blank'to a 4position serving tobreak contact between a pressed article and said fixedly-mounted diepiece, and means to rock the` pivotally-supported die pieces to the diepressing position of the die pieces for forming a yblank into a pressedarticle in cooperation with the punch and then to rock thepivotally-supported die pieces to an open position of the die pieces forbreaking contact between the pressed article and the ixedly` mounted diepiece and lifting the pressed article partially out of contact with thepivotally-supported die pieces.

References Cited in the le of this patent UNITED STATES PATENTS1,224,805 Stevenson May 1, 1917 1,266,963 Limont May 21, 1918 1,428,219l Crawford Sept. 5, 1922 1,883,079 Strickland Oct. 18, 1932 1,942,666Schwartz Jan. 9, 1934 2,158,434 ASchwartz May 16, 1939 2,275,174Clements Mar. 3, 1942 2,302,674 Carter Nov. 24, 1942 2,540,457 Rice Feb.6, 1951 2,541,544 Rahaim Feb. 13, 1951 2,680,286 Willgoos June 8, 19542,700,906 Allen Feb. 1, 1955

